This paper presents a stochastic simulation model for the growth of multiple matrix cracks in composite laminates subjected to both static and fatigue loads. Working within the premise of ply-elasticity, a new concept of effective flaws is introduced which replaces the conventional constant ply strength criterion. Thus, the model consists of an application of fracture mechanics and a rational representation of material flaw distributions. Simulation examples are presented on [0 2 /90 2 ] s and [0 2 /90 3 ] s graphite-epoxy laminates which undergo characteristic transverse cracking under uniaxial tension.

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In this paper, a new configuration of drop-shaped tube is proposed to improve the finned-tube thermo-flow performance. As the basic heat exchanger element of a Direct Air Cooled Condenser (DACC), the performance of finned tubes is very important to the optimal design of DACCs. Under turbine rated load (TRL) conditions and various frontal air velocities, the airside flow and heat transfer performance of single row flattened finned tubes and drop-shaped finned tubes are numerically investigated. The flow field, temperature field and thermo-flow characteristics are analyzed. Experimental verification and field coordination (synergy) analysis are carried out, with the simulation results agreeing well with experimental results. The performance of pressure drop, heat transfer coefficient and power consumption of these 4 Schemes are comprehensively compared and evaluated. When compared to the flattened finned tube the pressure drop of the drop-shaped Scheme 4 tube reduced by 5.9 % while the heat transfer coefficient reduced by 2.8 % at a frontal velocity of 1.8 m/s. Scheme 4 produces the best thermo-flow performance, especially at low air velocity, benefiting from a lower pressure drop and a moderate heat transfer coefficient.

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